High Performance Series/Parallel Boost/Buck DC/DC Converter as a Visible Light Communication HB-LED Driver Based on Split Power

This work proposes a High-Brightness LED (HB-LED) driver for Visible Light Communication (VLC) based on two converters, a high frequency Buck DC/DC converter and a low frequency Boost DC/DC converter, connected in series with respect to the LED load and connected in parallel at the input. This topology is called a Series/Parallel Boost/Buck DC/DC Converter. A VLC system needs to do two different tasks: biasing the HB-LED and generating the communication signal. These typically have different power requirements, the bias power is 3/4, while the communication power is 1/4 of the total power. The requirements of each are also different: the communication signal requires a high frequency, fast output response, while the biasing control requires a converter with a slow output voltage response. The proposed architecture takes advantage of the differences between the two tasks and achieves high efficiency and high communication performance by means of splitting the power between the two DC/DC converters. A high frequency Buck DC/DC converter generates the communication signal, while the low frequency Boost DC/DC converter is responsible for biasing the LEDs. This technique allows most of the DC biasing power to be processed by the low frequency converter (achieving high efficiency), keeping the high frequency converter delivering the communication power (achieving high communication performance). To provide experimental results, the proposed VLC HB-LED driver was built and validated by reproducing a 64-QAM with a bit rate up to 1.5 Mbps, reaching 91.5% overall efficiency.